Fuse-plug



w. n. WQOLLEY.

- FUSE PLUG.

APPLICATION FILED IULYIT. 19H.

1,308,518. I I .PatentedJulyl, 1919.

UNITED STATES PATENT OFFICE.

WALTON D. WOOLLEY, OECHIOAGO, ILLINOIS, ASSIGNOR' TO KILLARK. ELECTRIC MANUFACTURING COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

Specification of Letters Patent.

FUSE-PLUG.

Application filed July 17, 1917. ,Serial No. 181,048.

To all whom it may concern Be it known that I, WALTON D. Woonnnr,

a citizen of the United States, residing at the city of Chicago,-county of Cook, Stateof Illinois, have invented a certain new and useful Improvement in F use-Plugs, of which the following is a specification,-reference being had to the accompanying drawing, formin ,a part thereof.

lhis invention relates generally to electric safety fuses or cut-outs and, more especially, to a certain new and useful improvement in that type of safety fuses or cut-outs commonly known as fuse-plugs' Fuses of the type stated comprise a fusible element which, when the fuse or plug is inserted or placed in an electric circuit, is adapted and designed to carry or conduct the normal current of the circuit and to blow or fuse on an overload or abnormal current; the circuit being thereby opened or damage from such overload or excess of current. have heretofore been usually so constructed that, on a burning or blowing out of the fusible element, the plug, although, except So far as I am aware, fuse-plugs,

Fig. 4 is a similar view of the body or inner member of the plug;

Fig. 5 is an elevational view of the plu Fig. 6 is a perspective view of one of t e riinewable fusible elements or strips of the P Fig. 7 is a sectional view of a slightly ,modified form of the outer or casing-member of the plug;

Fig. 8 is a sectional view 'of a slightly modified fuse-plug embodying my inven. tion; and

Fig. 9 is a able fusible e ement or strip of the modified fuse-plug of Fig. 8.

As illustrated in the said drawing, in which like reference characters refer to like parts throughout the several views, my present fuse-p111 comprises, generally speaking,substant1ally but three readily separable members or parts, namely, a body-member, afusible element, and a casing, the casing forming one of the terminals, and being also the socket-engaging member, of the plug.

The fusible element is in: theform preferably of a thin strip or ribbon of suitable fusible metal or alloy adaptedand designed to conduct or-carry the normal current of for its fusible element, substantially unal' the circuit in which the particular plug may fected bysuch occurrence, was discarded as useless by the user.

The principal object of my present invention is to provide an efficient fuse-plug of few readily assembled members so constructed and cooperating that the plug may be easily taken apart and the fusible element inexpensively renewed with convenience and facility, repeated use of the other and generally more costly members or parts of the plug being thereby obtained and a consequent saving of expenseand economy of material effected.

With the above and other objects in view, my present invention resides in certain novel features of form, construction, arrangement, and combination of parts, all as hereinafter described and afterward pointed out in the claims.

In the accompanying drawing,

Figure 1 is a sectional view of a fuse-plug embodying my invention in preferred form; Fig. 2 is a plan view of the same;

Fig. 3 is an elevational view, partly in section, of the casing or outer member of the be inserted, this strip having a somewhat elongated end-portion 1 and an intermediate portion 2 of reduced cross-section to blow or fuse on approximately a predetermined overload or excess of current beyond the normal current of the circuit. The opposite end-portion of the strip, as hereinafter more fully appears, extends into or through an aperture in the body-member to form, directly or indirectly, the end or center contact or terminal of the plug and, in the preferred form of the plug, is reinforced by and includes a fixed section of somewhat lperspective view of the renewheavier metal bent intermediate its ends to oppositely project yieldingly laterally away i from the strip, as seen'in Fig. 6.

at indicates the, body-member of the plug, which is preferably, asshown, a, substantially cup-shaped section of porcelain, fiber, or other suitable insulation material molded or otherwise formed into the desired shape, member 4 having an interior chamber or cavity 5 and being for the greater part of its length spirally corrugated or threaded, as at 6, upon its outer surface or periphery. Approximately centrally through its end wall, member 4 is provided with an aperture or slot 7 to accommodate the reinforced end-portionof the fuse-strip. At its rim, member 4 is cut away or otherwise formed to provide a second aperture 8' for the opposite end-portion 1 of the fuse-strip.

The casing or outer member of ,the plug is substantially of unitary construction and comprises a ring or annulus 9 of suitable in-' sulation material, which is preferably cut away. as at. 10, to provide a seat for a mica disk or the like 11, the annulus or ring 9 with its disk 10 forming a so-called lid adapted, whenthe parts of the plug are as sembled, to close the open end of chamber 5 of member 4 and provide a window through which the condition of the fusestrip within member 4 may be observed. Permanently holding mica-disk 11 to its seat, is a metallic tubular member or shell 12,-onc, or the upper, end of which-is disposed within' the aperture of, and crimped or otherwise rigidly fixed to, ring 9, as seen particularly in Figs. 1 and 3. Shell 12 is of a length and diameter to correspond ap proximately with the length and exterior diameter of member 4 and is correspondingly corrugated or threaded, as at 13, the casing being adapted not only to removably fit upon and embrace, and to separably engage threadedly at its shell 12 with, bodymember 4, as illustrated in Figs. 1 and 5, but to also operatively engage threadedly with the usual plug-socket (not shown) included in the circuit to be protected.

In assembling the parts of the plug, a fuse-strip is drawn at its end-portion 1 endwise through aperture 7 to seat contactpiece 3 upon the outer face of the end-wall of member 4 and to dispose its intermediate pinched flatwise upon the strip to pass with the strip through the aperture 7-. The contact-piece 3 being seated upon, and intermediate strip-portion 2 being disposed withm, member 4as described, the tips 3 assume their normal lateral position relatively to the strip and thereby engage upon the in; ner face of the end-wall of member 4 and removably hold the contact-piece 3 operatively to its seat, as seen in Fig. 1. Endportion 1 of the strip is now passed outwardly through opposite or side-wall aperture 8 and then bent downwardly to extend lengthwise along the. threaded face of member 4, laterally projecting shoulders 14 on the strip being adapted to engage the wall of member 4 at opposite sides of said outlet aperture 8 to properly position and hold the fuse-strip relatively to body-member 4. A casing is then threaded upon the body-member and the thin bent end-portion 1 of the strip tightly wedged, in such operation, between body-member 4 and shell 12. The fuse-strip is thereby firmly held in operative position in the plug and in electrical contact or engagement with shell 12, shell 12 forming the side contact or terminal of the plug. It may be here stated that the shoulders 14 also hold the strip from being further drawn'through the aperture 8 during the threading of the casing upon body-member 4. The plug may now be employed as -an ordinary or standard plug and threaded into the usual plug-socket, the lid of the casing providing means for the convenient seating and unseating of the plug and the shell of the casing providing means for the mechanical and electrical engagement of the plug with the socket. On a blowing or fusing of the fuse-strip of theplug, the plug may be conveniently engaged at its ring 9 and unscrewed from such socket, the casing then unscrewed from the bodymember of the plug, an annular series of recesses 15 on the end wall of member 4 providing finger-grips to facilitate separation of casing and body-member, the parts of the blown strip removed, and a new strip substituted or inserted and the parts again operatively assembled, as described, when the plug is again ready for use. IVhile the spring tips 3 sufficiently engage with bodymember 4to'hold contact-piece 3 to its seat on a blowing of the strip, the contact-piece 30f a blown strip may be conveniently removed or pried from its seat for the substitution of a second strip by positive outward pressure or pull exerted thereupon by meansof any suitable tool (not shown). If desired, c0ntactpiece 3 of the fuse-strip may have stamped thereupon as illustrated any suitable mark or number to indicate the normal ampere carrying capacity of the strip. Side-wall aperture 8, as well as also preferably an additional aperture 16 provided in the rim of member 4, serve as vent openings for the escape from the plug of the gases generated on a blowing or fusing of a use strip. 1

In Fig. 7, I have shown a slightly modified form of casing-member for the plug.

In this form, the mica disk 11' and the upper end of shell 12 are embedded in the ring or annulus 9' during the manufacture of rlng 9, the casing so formed being substantially an integral structure. i

In Figs. 8 and 9, I show a slightly modified fuse-plug and its fusible element or strip. In this form of plug, the body-memher and casing are substantially similar in all respects to the body-member and easing of the preferred form of plug shown in Figs. 3 and 4 and are accordingly identified by the same reference characters. The fusibleelement or strip, however, has, as shown,

- elongated end-portions 1' and 17 an interform of strip, and a second pair of outwardly projecting lateral shoulders 18 in lieu of the shoulders 3 of the preferred form of strip. In assembling this form of my fuseplug, the end-portion 17 of the strip is projected outwardly of body-men1ber 4 through aperture 7 and shoulders 18 engaged with the inner face of end wall of member 4. The outwardly projecting part of end-portion 17 of the fuse-strip is then folded or bent upon itself, as illustrated in Fig. 8, beneath the end wall of the body-member,

4, to directly provide the center terminal or end-contactof the plug. Otherwise the assembling of this form of plug is approximately similar to the assembling of the preferred form previously described, the shoulders 18 removably' holding the bent end-portion 17 of the stri to its seat on a blowing of the strip. If esired, end-portion 17 of the fuse-strip may similarly have stamped thereupon, as shown, any suitable mark or number to indicate the normal ampere carrying capacity of the strip. j I am aware that minor changes in the form; construction, arrangement, and combination of the several parts of my new fuse-plug may be made and substituted for those herein shown and described without departing from the .nature and principle of my invention. Y

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A fuse-plug including, in combination, a cup-shaped body-member, a renewable fuse-strip disposed with an intermediate portion within the chamber of the bodymember and an end-portion projecting exteriorly thereof, and a removable unitary casing comprising a lid for closing the open end of the chamber of the body-member and a terminal-forming shell of approximately uniform. diameter throughout engagin separately with the body-member and t e projecting end-portion of the strip.

2. A fuse-plug including, in combination, an exteriorly threaded cup-shaped bodymember, a renewable fuse-strip having an intermediate portion disposed within the chamber of the body-member and an endportion projecting exteriorly thereof, and

1 a unitary casing removably threaded upon the body-member and comprising a lid for closing the open end of the chamber of the body-member and a threaded terminal-forming shell separably engaging the projecting end-portion of the strip.

3. A 'fuse-plu including, in combination,

an exteriorly t readed cup-shaped bodymember, a renewable fuse-strip disposed with an intermediate portion within the chamber of the body-member and an endportion projecting exteriorly thereof, the other end-portion of the strip being adapted for electrical contact with the center contact of a plug-socket, and a unitary casing removably threaded upon the body-member and comprising a lid for closing the open end of the chamber of the body-member and a terminal-forming shell separably engaging the projecting end-portion of the strip.

4. A fuse-plug including, in combination, an exteriorly threaded cup-shaped bodymember, a renewable fuse-strip disposed with an intermediate portion within the chamber of the body-member and an end portion. projecting exteriorly thereof, the other end-portion of the strip being adapted for electrical contact with the center contact of a plug-socket, and a unitary casing removably threaded upon the body-member and comprising a lid for closing the open end of the chamber of the body-member and a terminal-forming shell separably engaging the projecting end-portion of the strip, the projecting end-portion of the strip bein wedged between the shell and body- 'mem r in the threading of the casing upon the body-member.

5. In a fuse-plug, the combination with an exteriorly threaded chambered bodymember'having an aperture in its wall, of a fuse-strip having an intermediate portion disposed within the chamber of the bodymember and an end-portion projecting exthrough said aperture during the threading of the shell upon the body-member.

6. A renewable fuse-plug including a chambered body-member having an aperture in its w a1l,'in combination with a separable fuse-strip having an intermediate portion disposed within the chamber of the body-member and a reinforced shouldered contact forming end, portion extendin through said aperture, the shoulders of sai end-portion bei'ngalso disposed within the chamber of the body-member and engaging with the inner face of the wall thereof for normally holding the strip from endwise movement through said aperture,

7. A renewable fuse-plug strip having a reinforcing terminal-forming section fixed upon an end-portion thereof, said section in cluding portions disposed flatwise upon opposite sides of "the strip, the ends of said portions forming body -member engaging shoulders for the strip.

8. A renewable fuse-plug including a separable fuse-strip, in combination with an externally threaded cup-shaped body-member, and a unitary casing fitting removably upon the body-member and comprising an insulation window closing the open end of the chamber of the body-member and a' threade terminal-forming shell.

9. In a renewable fuse-plug, a casing comprising, as a unitary structure, a ring of insulation material, an insulation -window disposed in the ring for closing the aperture thereof, and a body-member engaging-shell rigidly fixed at one end to the ring.

10. A fuse-plug shell comprising a ring of .insulation material, an insulation-window seated in the ring, to close the aperture thereof, and a threaded metallic tube having one end fixed to the ring and permanently holding the window to its seat.

11. A renewable fuse-plug including, in combination, an exteriorly threaded cupshaped body-member, a replaceable fusestrip having an intermediate portion disposed within the chamber of thebody-memher and an end-portion projecting exteriorly thereof, and a unitary casing removably threaded upon the body-member and comprising an insulation-ring and a threaded terminal-forming shell, the shell separably engaging electrically with the projecting end-portion of the strip.

12. A renewable fuse-plug including, in combination, an exteriorly threaded eupshaped body-member, a replaceable fusestrip having an inter-mediate portion disposed within the chamber of the body member and an end-portion projecting exteriorly thereof, and aunitary casing removably threaded upon thebod'y-member and comprising an insulation-ring and a threaded terminal-forming shell separably engaging electrically with the projecting-end portion of the strip, the pro ecting end-portion of the strip being wedged between the shell and body-member in the threading of the casing upon the body-member.

In testimony whereof, I have signed my name to this specification.

WALTON D. W'O OLLE Y. 

